Conventionally, a wiring board is known that contains inside an electronic component such as a capacitor or an inductor. As an example of such a wiring board, a wiring board including a glass epoxy substrate, which is a core, that contains inside a stacked structure of ceramic capacitors may be raised. In this wiring board, wirings are formed at front and back surfaces of the glass epoxy substrate, and the wiring at the both surfaces and electrodes of the stacked ceramic capacitors are connected through via wirings formed in the glass epoxy substrate (see Patent Document 1, for example).
Meanwhile, a wiring board is known in which embedded wirings are provided at one side of an insulating layer (see Patent Document 2, for example). When containing an electronic component inside such a wiring board, it is impossible to adopt a connection structure similar to the above described wiring board for connecting the embedded wirings with electrodes of the electronic component. Thus, as a method of connecting the embedded wirings with the electrodes of the electronic component, for example, a method of using a conductive paste may be considered.
However, there is a problem that sufficient connection reliability cannot be obtained by the method of connecting the embedded wirings with the electrodes of the electronic component using the conductive paste.    Patent Document 1: Japanese Laid-open Patent Publication No. 2013-84692    Patent Document 2: Japanese Laid-open Patent Publication No. 2012-146793